Diseases of the cardiovascular system affect millions of people each year and are a leading cause of death in the United States and throughout the world. The cost to society from such diseases is enormous, both in terms of lives lost and the cost of treating cardiac diseased patients through surgery. It is well known that certain of these diseases may result in disorders of the cardiac valves. Some of these diseases may result in endocarditis, which is an inflammation of the endocardium or the membrane lining the heart, while other diseases, such as rheumatic fever, may cause shrinkage or separation of the orifice of a valve. The resulting defects in the cardiac valves, which include the narrowing of the valve commisores (valvular stenosis) and/or the defective closing of the valve (valvular insufficiency), tend to hinder the normal operation of the heart by causing an accumulation of blood in a heart cavity or regurgitation of blood past the valve. In many cases, complete valve replacement is required because of damage caused to heart muscle by prolonged valvular stenosis or insufficiency.
Although replacement of heart valves has become relatively common, i.e., as many as 80,000 heart valve prostheses are implanted in the United States alone, the procedure is lengthy and traumatic, and in many instances, the surgical technique requires breaking of bones. In a conventional heart valve prosthesis procedure, the surgeon typically performs a sternotomy, cuts off the blood to the heart and then stops the heart from beating in order to replace the valve. Thus, in order to perform this procedure, the surgeon makes a long incision down the middle of the chest, saws through the entire length of the sternum, spreads the two halves of the sternum apart, and then performs several procedures necessary to stop the heart and attach the patient to a cardiopulmonary bypass machine to continue the circulation of oxygenated blood to the rest of the body while the cardiac valve is being replaced.
During the heart valve replacement procedure, the pericardium is opened to expose the heart. To improve exposure of the heart, sutures are typically fixed to the edges of the pericardial opening to retract the opening and then tied to the patient's chest to secure the sutures. The heart is then cannulated to establish vents and cardiopulmonary bypass (CPB), and to provide cardioplegia delivery. Once CPB is established, the heart is isolated by clamping the aorta and a cardioplegia solution is infused to arrest the heart. In the instance of aortic or mitral valve replacement, an aortotomy or atriotomy is performed to expose the defective cardiac valve. After the valve is excised, a valve prosthesis can be implanted.
To implant the valve prosthesis, sutures are placed in the annulus and tagged. While keeping the sutures organized, which can prove to be a complicated task, the sutures are placed in the sewing ring of the valve prosthesis. The valve prosthesis is then seated and the sutures are tied to secure the valve prosthesis in place. To complete the procedure, the aortotomy or atriotomy is closed, the heart is vented and resuscitated, the vents and other cannulas are removed, the incisions are closed, and then the sternotomy is closed.
As noted above, the conventional procedure is lengthy and traumatic. The typical sternotomy is invasive and results in prolonged and difficult recovery. The conventional procedure also tends to be complicated by the presence of a large number of instruments, sutures and cannulas that potentially clutter the access to the heart and by the need to quickly place sutures in the annulus and valve prothesis while keeping the sutures organized. Thus, it would be desirable to provide an apparatus that facilitates a less invasive procedure, that facilitates access to and exposure of the heart, and that facilitates the organization and placement of sutures as well as instruments and cannulas during the surgical procedure.